1. Field of the Invention
The present invention relates to a method for producing a crystallographically oriented ceramic, and more specifically, it relates to a method for producing a crystallographically oriented ceramic used for a piezoelectric/electrostrictive component.
2. Description of the Related Art
Hitherto, regarding a method for producing a crystallographically oriented ceramic, piezoelectric thin films as typified by thin films composed of lead zirconate titanate (hereinafter, referred to as “PZT”) have been formed by depositing films using, for example, physical vapor deposition (PVD) such as sputtering, chemical vapor deposition (CVD), and a sol-gel method and firing the films. In the vapor phase deposition, however, it is difficult to increase the film thickness to, for example, 1 μm or more. The use of the sol-gel method sometimes causes a reduction in density, thus failing to provide satisfactory piezoelectric properties. For example, Patent Document 1 discloses that a method includes forming seed crystals of a piezoelectric PZT thin film so as to have a grain size of 0.05 μm to 1 μm, the seed crystals being oriented either in the (100) plane when formed by a sol-gel method or in the (111) plane when formed by sputtering, and performing hydrothermal synthesis to form a thick film. For this piezoelectric film, it is possible to increase the thickness relatively easily and perform fine patterning. Patent Document 2 discloses that a method for producing a highly oriented PZT thin film includes growing a PZT thin film by sputtering while irradiating the growth surface of a crystal growth substrate with an electron beam. Patent Document 3 discloses that a method for producing a piezoelectric element having a piezoelectric thin film interposed between a top electrode and a bottom electrode includes forming titanium islands, serving as nuclei of a piezoelectric substance, on grain boundaries of the bottom electrode, whereby satisfactory piezoelectric properties are provided.